1. Field of the Invention
The present invention relates to an optical apparatus and more particularly to an optical apparatus adapted for use in image taking and television image taking, an optical apparatus driving unit and a camera system.
2. Related Background Art
In the following there will be explained, with reference to FIG. 1, a conventional optical apparatus employed for example for television image taking. On the external periphery of a main body 1 of the optical apparatus, there is provided a rotatable operation ring 2, which is either manually driven or electrically driven from a drive unit 4 provided on the main body 1 of the apparatus, for driving optical adjustment means such as a movable lens group (not shown) provided in a casing 3.
Inside the drive unit 4, there are housed a motor and a control circuit for electrically driving the operation ring 2, and the manipulation of an electrical operation switch 5 or the like provided on the external face of the drive unit 4 drives the motor thereby driving the operation ring 2.
In such optical apparatus capable of manual drive and electrical drive for the movable lens group, operation is switched between manual drive and electrical drive generally by the manipulation of a clutch mechanism provided with a switching lever. An example of such a clutch mechanism is shown in FIG. 2. The clutch mechanism is provided, between an operation gear 6 formed on the operation ring 2 and an output gear 8 of a motor 7, with an idle gear 9 slidable in the axial direction of a shaft 10 by the operation of a switch lever (not shown). In the electrical drive, the switch lever is operated to slide the idle gear 9 into a position in mesh with the operation gear 6 and the output gear 8, whereby the driving force of the motor 7 can be transmitted to the operation ring 2 through the idle gear 9. During manual operation, the switch lever is operated to slide the idle gear 9 to a position disengaged from the operation gear 6 and the output gear 8. Thus, conventionally, the operation of operation ring 2 is switched between manual drive and electrical drive by connecting or disconnecting the power transmission path from the motor 7 to the operation ring 2, utilizing a clutch mechanism.
However, in such conventional optical apparatus in which the transmission path of the motor power is connected or disconnected by the operation of the switch lever thereby switching between the manual drive and the electric drive, it is necessary to manipulate the switch lever of the clutch mechanism at each switching between the manual drive and the electrical drive operation, thus involving cumbersome operations and hindering prompt switching between the manual drive and the electrical drive operation.
Also, during an actual image taking operation, in the course of an electrical drive, the operator may manually manipulate the operation ring 2 so as to forcedly stop the electrical drive, or to drive the operation ring in the opposite direction, or to increase or decrease the speed of the electrical drive.
In the above-described clutch mechanism, however, it is difficult to execute a manual operation in the course of the electrical drive.
In recent TV lenses, therefore, switching between the electrical drive mode and the manual drive mode for the zoom lens has been made using a switching mechanism capable of electrical switching (on/off), such as an electromagnetic clutch, thereby avoiding manual switching.
Such function will be explained with reference to FIG. 3. In FIG. 3, there are shown a main body 11 of an image taking lens, a zoom drive ring 11a, an idler gear 16 in mesh with and rotated by the zoom drive ring 11a in the main body of the image taking lens, a zoom driving motor 17, a drive circuit 18 for driving the zoom driving motor 17, a D/A converter 19 for converting a digital drive signal from a CPU 24 (to be explained later) into an analog drive signal for supply to the drive circuit 18, an A/D converter 20 for converting an analog zoom control signal from a zoom control switch 21 (to be explained later) into a digital signal, a zoom control switch 21 for outputting a control signal from the exterior (the CPU 24 controls the present function), a connection on/off circuit 25 for turning on/off the connection of a clutch 26 (to be explained later) according to a connection signal from the CPU 24, and the clutch 26 capable of electrically turning on/off the connection represented by an electromagnetic clutch.
In the case where the zoom control switch 11 is not operated, the CPU 24 detects a manual operation state using a control signal supplied through the A/D converter 20. In such state, a release signal is supplied to the connection on/off circuit 25 in order to release the connection of the clutch 26. In response to such signal, the connection on/off circuit 25 releases the connection of the clutch 26. The release of the connection of the clutch 26 disengages the drive motor 17, whereby the zoom lens can be manually operated using the zoom drive ring 11.
When the zoom control switch 21 is operated, the CPU 24 detects an electric drive operation state using a control signal supplied through the A/D converter 20. In such state, a connection signal for connecting the clutch 25 is supplied to the connection on/off circuit 25, and the clutch 26 is connected in response to the signal.
On the other hand, when the zoom control switch 21 is operated, a control signal corresponding to the operation amount thereof is output. As described in the foregoing, the zoom control signal is supplied through the A/D converter 20 to the CPU 24, which converts the entered zoom control signal into a drive signal so as to output the signal to the D/A converter 19. The D/A converter converts the drive signal into an analog signal, which is used by the drive circuit 18 for driving the driving motor 17. As the clutch 26 is in the connected state, the driving torque of the driving motor 17 is transmitted through the idler gear 16 to the zoom drive ring 11, thereby electrically driving the zoom lens.
In this manner it is possible to switch between the electric mode and the manual mode, without manual switching, by switching the connection and disconnection of the clutch 26 in accordance with the operation of the zoom control switch 21.
However, in an actual image taking operation with the lens apparatus (and the camera), while the zoom lens is electrically driven, the operator may wish to manually operate the zoom drive ring in order to stop the electrical drive, to increase or decrease the driving speed, or even to reverse the driving direction by such manual operation.
In the conventional lens apparatus shown in FIG. 3, as the driving force from the driving motor is transmitted to the zoom lens through the clutch during an electrical drive operation, it is difficult to smoothly achieve a manual operation, such as stopping of the electrical drive, increasing or decreasing of the electrical driving speed, or reversing of the driving direction by manual manipulation.
It is still possible to switch from the electrical mode to the manual mode by detecting a manual operation during an electrical drive operation of the zoom lens. However, after such switching to the manual mode, in the case where the operator releases his hand from the zoom drive ring to restore the electrical drive operation, there are required complex operations, such as returning the zoom control switch to a neutral state and then operating the zoom control switch again, for switching to the electrical mode.
In consideration of the foregoing, an object of the present invention is to provide an optical apparatus enabling simple and prompt switching of manual drive and electrical drive of an optical member and also enabling a smooth manual operation in the course of the electrical drive.
Another object of the present invention is to provide an optical apparatus and an optical apparatus driving unit enabling a smooth manual operation in case a manual operation is executed in the course of an electrical drive of a zoom lens or the like, and also enabling to restart the electrical drive simply and promptly when the manual operation is released.
The above-mentioned objects can be attained, according to the present invention, by an optical apparatus comprising:
an optical member;
manual operation means for manually driving the optical member;
a driving motor for electrically driving the optical member;
determination means for deetermining the manual drive by the manual drive means or the electrical drive by the driving motor;
connection means for transmitting the drive force by the driving motor to the optical member with a predetermined connection torque; and
control means for varying the connection torque of the connection means according to the result of determination by the determination means.
According to the present invention, there is also provided an optical apparatus comprising:
an optical member;
manual operation means for manually driving the optical member;
a driving motor for electrically driving the optical member;
determination means for determining the manual drive by the manual drive means or the electrical drive by the driving motor;
connection means for transmitting the drive force by the driving motor to the optical member with a predetermined connection torque;
state detection means for detecting the state of the optical apparatus and outputting state detection information; and
control means for varying the connection torque of the connection means according to the result of determination by the determination means;
wherein the control means varies the connection torque also according to the state detection information from the state detection means.
According to the present invention, there is also provided an optical apparatus comprising:
an optical member;
manual operation means for manually driving the optical member;
a driving motor for electrically driving the optical member;
instruction operation means having an operation member and giving a drive instruction to the driving motor in response to the operation of the operation member;
determination means for determining the manual drive by the manual drive means or the electrical drive by the driving motor based on the drive instruction from the instruction operation means;
connection means for transmitting the drive force by the driving motor to the optical member with a predetermined connection torque; and
control means for varying the connection torque of the connection means according to the result of determination by the determination means;
wherein the control means varies the connection torque also according to the drive instruction from the instruction operation means.
According to the present invention, there is also provided an optical apparatus comprising:
an optical member;
manual operation means for manually driving the optical member;
a driving motor for electrically driving the optical member;
determination means for determining the manual drive by the manual drive means or the electrical drive by the driving motor;
connection means for transmitting the drive force by the driving motor to the optical member with a predetermined connection torque; and
control means for varying the connection torque of the connection means according to the result of determination by the determination means;
wherein the control means varies the connection torque, upon detection of an operation of the manual operation means during the electrical drive by the driving motor, according to the operation.
Still other objects of the present invention, and the features thereof, will become fully apparent from the following description of the embodiments.